AN2359 Datasheet, PDF (15/18 Pages) STMicroelectronics – Double output Buck-Boost converter with VIPerX2A

AN2359
Layout considerations
Table 11. Experimental results - V_IN=374V_DC
I_OUT1[mA] I_OUT2[mA] V_OUT1[V] V_OUT2[V] I_IN[mA]
0
0
24.16
5.098
0.513
10
30
23.99
5.094
1.852
50
150
24
5.094
7.04
80
240
24.03
5.085
10.66
100
300
24.028
5.071
13.14
0
300
41
5.03
6.68
100
0
21.93
5.1
7.221
P_IN[W]
0.21
0.74
2.82
4.26
5.26
2.67
2.89
P_OUT[W]
0.00
0.39
1.96
3.14
3.92
1.51
2.19
η[%]
0.00
53.01
69.75
73.71
74.66
56.47
75.92
Figure 16. Typical waveforms at 300V_DC and Figure 17. Typical waveforms at 300V_DC and
full load: commutation
full load: detail
5
Layout considerations
A proper PCB layout is essential for correct operation of any switch-mode converter and the
same basic rules have to be taken into account in order to optimize the current path,
especially in high current path routing.
Since EMI issues are related to layout, the current loop area has to be minimized. Moreover,
the control ground path has to be separated from power ground, in order to avoid any noise
interference between the control section and the power section.
All the traces carrying high currents have to be as short as possible, in order to minimize the
resistive and inductive effect.
A particular care has to be taken into account regarding the optimal routing of the input EMI
filter path and the correct placement of any single component (L₁ –R₁ very close to input
bulk capacitors, trace as short as possible…).
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